1. Field of the Invention
The invention relates to a panel of composite material for constructing an aircraft airframe or an aircraft wing and to a method of fabricating the same.
2. Description of the Related Art
An aircraft wing of composite material is constructed by forming a lower outside skin, an upper outside skin, spars and ribs separately, and then by fastening the lower outside skin, the upper outside skin, the spars and the ribs by using fastening means. Alternatively, an aircraft panel of composite material is constructed by forming a combined structure of composite material integratedly including a lower outside skin (or an upper outside skin), spars and ribs and then by fastening an upper outside skin (or a lower outside skin) to the combined structure by using fastening means.
The aircraft wing of composite material formed by fastening together the component members is a structure comprising a large number of component parts. Since work for assembling the aircraft wing needs special assembling jigs and complicated operations, the aircraft wing is costly.
The aircraft wing constructed by using the combined structure having either the lower outside skin or the upper outside skin is based on the conventional concept of structure. Thus, jigs and processes are complicated and hence the aircraft wing is costly.
The present invention has been made in view of the foregoing circumstances. Therefore, the object of this invention is to provide a panel of composite material having a greatly reduced number of component parts, and capable of being assembled by greatly reduced manhours and of being fabricated at a low cost, and a method of fabricating such a panel.
To achieve the above object, this invention is characterized by following features. That is, this invention is a method of fabricating a panel of composite material including two outside skins and stringers attached inside of the two outside skins for reinforcing the two outside skins, said method comprising the steps of: forming a plurality of stringers for reinforcing outside skins from dry preformed fibers; disposing the plurality of stringers at a predetermined interval and connecting adjacent two stringers with each other via a connecting member made from dry preformed fibers; setting the connected stringers and the connecting members into a forming mold and introducing resin into the forming mold to impregnate the dry preformed fibers of the stringers and the connecting members; curing the resin-impregnated stringers and the resin-impregnated connecting members to unite the resin-impregnated stringers and the resin-impregnated connecting members into one body of xe2x80x9cRudder Shapexe2x80x9d stringer; laminating a prepreg onto an outside-skin shaping mold; disposing the united stringers and connecting members onto the laminated prepreg; curing the laminated prepreg and the united stringers and connecting members to form an outside-skin part in which the stringers, the connecting members and an outside skin are united; and connecting two outside-skin parts with each other via a reinforcing member to form a panel of composite material.
According to the feature, since the stringers and the connecting member are integratedly made of fiber-reinforced resin, dimensional accuracy thereof may be improved. In addition, assembling time may be shortened because it is unnecessary to adjust a gap between the connecting member and the reinforcing member. Jig-setting time may be also shortened because any complicated mandrel is unnecessary for integratedly forming the stringers, the connecting member and the outside skin.
In the panel of composite material according to the invention, the outside-skin part, in which the stringers, the connecting member and the outside skin are united, is formed integratedly. The connecting member may have an extended portion protruding upward with respect to the stringers. The extended portion may be connectable by a fastener. Two outside-skin parts may be connected by connecting the respective extended portions via the reinforcing member with fasteners.
Alternatively, this invention is a method of fabricating a wing of composite material, said method comprising the steps of: forming a plurality of stringers for reinforcing outside skins of a wing from dry preformed fibers; disposing the plurality of stringers at a predetermined interval and connecting adjacent two stringers with each other via a connecting member made from dry preformed fibers; setting the connected stringers and the connecting members into a forming mold and introducing resin into the forming mold to impregnate the dry preformed fibers of the stringers and the connecting members; curing the resin-impregnated stringers and the resin-impregnated connecting members to unite the resin-impregnated stringers and the resin-impregnated connecting members into one body of xe2x80x9cRudder Shapexe2x80x9d stringer; laminating a prepreg onto a first outside-skin shaping mold that has a shape of an upper surface of the wing; laminating a prepreg onto a second outside-skin shaping mold that has a shape of a lower surface of the wing; disposing united stringers and connecting members and semicured front and rear spars onto the prepreg laminated onto the first outside-skin shaping mold; disposing united stringers and connecting members onto the prepreg laminated onto the second outside-skin shaping mold; curing the laminated prepreg, the united stringers and connecting members, and the front and rear spars, to form a first wing-outside-skin part in which the stringer, the connecting members, the front and rear spars and an outside skin are united; and curing the laminated prepreg and the united stringers and connecting members to form a second wing-outside-skin part in which the stringer, the connecting members and an outside skin are united; connecting the front and rear spars of the first wing-outside-skin part to the second wing-outside-skin part via a fastener; and connecting the respective connecting members of the two wing-outside-skin parts with each other via a reinforcing member to form a predetermined shape of the wing.